[单选题]
An electron is known ::(7; ivyr2e unnj+v: trz rwsto be confined t pr:gz0 pugz cu63,no7o a region of width 0.1 nm. What is an approxim7:gz 6p gpc3z nouru0,ate expression for the least kinetic energy it could have, in eV?
A. $2.7 \; eV$
B. $3.2 \; eV$
C. $3.8 \; eV$
D. $4.3 \; eV$
